Device and Method for Modifying the Shape of a Body Organ

ABSTRACT

An intravascular support device includes a support or reshaper wire, a proximal anchor and a distal anchor. The support wire engages a vessel wall to change the shape of tissue adjacent the vessel in which the intravascular support is placed. The anchors and support wire are designed such that the vessel in which the support is placed remains open and can be accessed by other devices if necessary. The device provides a minimal metal surface area to blood flowing within the vessel to limit the creation of thrombosis. The anchors can be locked in place to secure the support within the vessel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of pending U.S. application Ser. No.10/429,172, filed May 2, 2003, entitled “Device and Method for Modifyingthe Shape of a Body Organ,” which application is incorporated byreference as if fully set forth herein.

FIELD OF THE INVENTION

The present invention relates to medical devices in general, and inparticular to devices for supporting internal body organs.

BACKGROUND OF THE INVENTION

The mitral valve is a portion of the heart that is located between thechambers of the left atrium and the left ventricle. When the leftventricle contracts to pump blood throughout the body, the mitral valvecloses to prevent the blood being pumped back into the left atrium. Insome patients, whether due to genetic malformation, disease or injury,the mitral valve fails to close properly causing a condition known asregurgitation, whereby blood is pumped into the atrium upon eachcontraction of the heart muscle. Regurgitation is a serious, oftenrapidly deteriorating, condition that reduces circulatory efficiency andmust be corrected.

Two of the more common techniques for restoring the function of adamaged mitral valve are to surgically replace the valve with amechanical valve or to suture a flexible ring around the valve tosupport it. Each of these procedures is highly invasive because accessto the heart is obtained through an opening in the patient's chest.Patients with mitral valve regurgitation are often relatively frailthereby increasing the risks associated with such an operation.

One less invasive approach for aiding the closure of the mitral valveinvolves the placement of a support structure in the cardiac sinus andvessel that passes adjacent the mitral valve. The support structure isdesigned to push the vessel and surrounding tissue against the valve toaid its closure. This technique has the advantage over other methods ofmitral valve repair because it can be performed percutaneously withoutopening the chest wall. While this technique appears promising, someproposed supports appear to limit the amount of blood that can flowthrough the coronary sinus and may contribute to the formation ofthrombosis in the vessel. Therefore, there is a need for a tissuesupport structure that does not inhibit the flow of blood in the vesselin which it is placed and reduces the likelihood of thrombosisformation. Furthermore, the device should be flexible and securelyanchored such that it moves with the body and can adapt to changes inthe shape of the vessel over time.

The present invention is an intravascular support that is designed tochange the shape of a body organ that is adjacent to a vessel in whichthe support is placed. In one embodiment of the invention, the supportis designed to aid the closure of a mitral valve. The support is placedin a coronary sinus and vessel that are located adjacent the mitralvalve and urges the vessel wall against the valve to aid its closure.

The intravascular support of the present invention includes a proximaland distal anchor and a support wire or reshaper disposed therebetween.The proximal and distal anchors circumferentially engage a vessel inwhich the support is placed. A support wire is urged against the vesselby the proximal and distal anchors to support the tissue adjacent thevessel.

In one embodiment of the invention, the proximal and distal supports aremade from a wire hoop that presents a low metal coverage area to bloodflowing within the vessel. The wire hoops may allow tissue to grow overthe anchors to reduce the chance of thrombosis formation. The wire hoopshave a figure eight configuration and can expand to maintain contactwith the vessel walls if no vessel expands or changes shape.

In another embodiment of the invention, the proximal and distal anchorsof the intravascular support are rotationally offset from each other.Locks on the support wire allow a physician to ensure that the anchorshave been successfully deployed and prevent the support wire fromcollapsing within a vessel.

SUMMARY OF THE INVENTION

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates an intravascular support for changing the shape of aninternal body organ in accordance with one embodiment of the presentinvention;

FIG. 2 illustrates one method of deploying an intravascular support inaccordance with the present invention;

FIG. 3 illustrates one embodiment of the intravascular support inaccordance with the present invention;

FIG. 4 illustrates a distal anchor of the embodiment shown in FIG. 3;

FIG. 5 illustrates a proximal anchor of the embodiment shown in FIG. 3;

FIGS. 6A-6C are cross-sectional views of crimp tubes for use with oneembodiment of the present invention;

FIG. 7 illustrates a proximal lock at the proximal end of theintravascular support as shown in FIG. 3;

FIG. 8 illustrates how the embodiment of the intravascular support shownin FIG. 3 is deployed from a catheter;

FIG. 9 illustrates an intravascular support in accordance with anotherembodiment of the present invention;

FIG. 10 illustrates a distal anchor of the intravascular support shownin FIG. 9;

FIG. 11 illustrates a proximal anchor of the intravascular support shownin FIG. 9;

FIG. 12 illustrates yet another embodiment of an intravascular supportin accordance with the present invention;

FIG. 13 illustrates a distal anchor of the intravascular support shownin FIG. 12;

FIG. 14 illustrates a proximal anchor of the intravascular support shownin FIG. 12;

FIG. 15 illustrates an anchor and strut according to another embodimentof the invention;

FIG. 16 illustrates a double loop anchor according to another embodimentof the invention;

FIG. 17 illustrates a double loop anchor with a cross strut according toanother embodiment of the invention; and

FIG. 18 illustrates an anchor with torsional springs according toanother embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As indicated above, the present invention is a medical device thatsupports or changes the shape of tissue that is adjacent a vessel inwhich the device is placed. The present invention can be used in anylocation in the body where the tissue needing support is located near avessel in which the device can be deployed. The present invention isparticularly useful in supporting a mitral valve in an area adjacent acoronary sinus and vessel. Therefore, although the embodiments of theinvention described are designed to support a mitral valve, thoseskilled in the art will appreciate that the invention is not limited touse in supporting a mitral valve.

FIG. 1 illustrates a mitral valve 20 having a number of flaps 22, 24 and26 that should overlap and close when the ventricle of the heartcontracts. As indicated above, some hearts may have a mitral valve thatfails to close properly thereby creating one or more gaps 28 that allowblood to be pumped back into the left atrium each time the heartcontracts. To add support to the mitral valve such that the valvecompletely closes, an intravascular support 50 is placed in a coronarysinus and vessel 60 that passes adjacent one side of the mitral valve20. The intravascular support 50 has a proximal anchor 52, a distalanchor 54, and a support wire 56 or reshaper extending between theproximal and distal anchors. With the anchors 52 and 54 in place, thesupport wire 56 exerts a force through the coronary sinus wall on thepostero-lateral mitral valve 20 thereby closing the one or more gaps 28formed between the valve flaps. With the intravascular support 50 inplace, the function of the mitral valve is improved.

As will be explained in further detail below, each of the proximal anddistal anchors 52, 54 preferably circumferentially engages the wall ofthe vessel 60 in which it is placed. The support wire 56 is secured to aperipheral edge of the proximal and distal anchors such that the supportwire is urged by the anchors against the vessel wall. Therefore, thesupport wire 56 and anchors 52, 54 present a minimal obstruction toblood flowing within the vessel.

FIG. 2 shows one possible method of delivering the intravascular supportof the present invention to a desired location in a patient's body. Anincision 80 is made in the patient's skin to access a blood vessel. Aguide catheter 82 is advanced through the patient's vasculature untilits distal end is positioned adjacent the desired location of theintravascular support. After positioning the guide catheter 82, adelivery catheter and advancing mechanism 84 are inserted through theguide catheter 82 to deploy the intravascular support at the desiredlocation in the patient's body. Further detail regarding one suitableadvancing mechanism 84 is described in commonly assigned U.S. patentapplication Ser. No. 10/313,914, filed Dec. 5, 2002, the disclosure ofwhich is hereby incorporated by reference.

FIG. 3 illustrates one embodiment of an intravascular support inaccordance with the present invention. The intravascular support 100includes a support wire 102 having a proximal end 104 and a distal end106. The support wire 102 is made of a biocompatible material such asstainless steel or a shape memory material such as nitinol wire.

In one embodiment of the invention, the support wire 102 comprises adouble length of nitinol wire that has both ends positioned within adistal crimp tube 108. To form the support wire 102, the wire extendsdistally from the crimp tube 108 where it is bent to form a distal stoploop (see 121 in FIG. 4) having a diameter that is larger than thelumens within the distal crimp tube 108. After forming the distal stoploop, the wire returns proximally through the crimp tube 108 towards theproximal end of the support 100. Proximal to the proximal end of thecrimp tube 108, is a distal lock 110 that is formed by the support wirebending away from the longitudinal axis of the support 102 and thenbeing bent parallel to the longitudinal axis of the support before beingbent again towards the longitudinal axis of the support. Therefore, thebends in the support wire form a half 110 a of the distal lock that isused to secure the distal anchor in the manner described below. From thedistal lock 110, the wire continues proximally through a proximal crimptube 112. On exiting the proximal end of the proximal crimp tube 112,the wire is bent to form an arrowhead-shaped proximal lock 114. The wireof the support 102 then returns distally through the proximal crimp tube112 to a position just proximal to the proximal end of the distal crimptube 108 wherein the wire is bent to form a second half 110 b of thedistal lock 110.

Support wire 102 has a length that is selected based on its intendeddestination within a patient's vessel. For use in supporting a mitralvalve, the support wire is preferably between one and six inches longand has a curved bend between its proximal end 104 and distal end 106with a radius of curvature between 1 and 3 inches and most preferablywith a radius of curvature of 1.8 inches. In addition, the wire used toform the support wire 102 is flexible enough to move with each heartbeat(thereby changing the force applied to the mitral valve annulus duringthe heartbeat) and stiff enough to support the mitral valve. In oneembodiment, the wire used to form the support wire 102 is made ofnitinol having a modulus of elasticity of 5-20×10⁶ psi and a diameter ofbetween 0.0110″ and 0.0150″ and most preferably 0.0140″. Other shapememory materials may be used for support wire as well.

At the distal end of the support wire 102 is a distal anchor 120 that isformed of a flexible wire such as nitinol or some other shape memorymaterial. As is best shown in FIGS. 3 and 4, the wire forming the distalanchor has one end positioned within the distal crimp tube 108. Afterexiting the distal end of the crimp tube 108, the wire forms a figureeight configuration whereby it bends upward and radially outward fromthe longitudinal axis of the crimp tube 108. The wire then bends backproximally and crosses the longitudinal axis of the crimp tube 108 toform one leg of the figure eight. The wire is then bent to form a doubleloop eyelet or loop 122 around the longitudinal axis of the support wire102 before extending radially outwards and distally back over thelongitudinal axis of the crimp tube 108 to form the other leg of thefigure eight. Finally, the wire is bent proximally into the distal endof the crimp tube 108 to complete the distal anchor 120.

The distal anchor is expanded by sliding the double eyelet 122 of thedistal anchor from a position that is proximal to the distal lock 110 onthe support wire to a position that is distal to the distal lock 110.The bent-out portions 110 a and 110 b of support wire 110 are spacedwider than the width of double eyelet 122 and provide camming surfacesfor the locking action. Distal movement of eyelet 122 pushes thesecamming surfaces inward to permit eyelet 122 to pass distally of thelock 110, then return to their original spacing to keep eyelet 122 inthe locked position.

The dimensions of the distal anchor are selected so that the diameter ofthe distal anchor in a plane perpendicular to the axis of the lumen inwhich the anchor is deployed is preferably between 100% and 300%, mostpreferably between 130% and 200%, of the diameter of the lumen prior todeployment. When treating mitral valve regurgitation by placement of thedevice in the coronary sinus, the diameter of the coronary sinus mayexpand over time after deployment. Oversizing the anchor combined withthe inherent deformability and recoverability properties of the anchormaterial (particularly nitinol or some other shape memory material)enables the anchor to continue to expand from its initial deploymentsize as the lumen distends and expands over time.

Upon expansion, the distal anchor circumferentially engages the vesselwall with a radially outwardly directed force that is distributedunequally around the circumference of the anchor by distending thevessel wall in variable amounts along the axial length of the anchor.The unequal distribution of force helps the anchor contact the lumenwall securely by creating bumps and ridges that are not parallel to thecentral axis of the lumen. In its expanded configuration the distalanchor's diameter is at least 50%-500% and most preferably 100%-300% ofthe anchor's diameter in the unexpanded configuration. The opencross-sectional area of the lumen through the anchor is at least 50% andmost preferably 80%-100% of the lumen cross sectional area prior toredeployment of the anchor.

In addition, the metal coverage of the anchor, as defined by thepercentage of the lumen surface area through which the anchor extendsthat is exposed to a metal surface, is between 5% and 30% and mostpreferably 10%. The wire used to form the distal anchor 120 ispreferably nitinol having a diameter of between 0.0110″ and 0.0150″ andmost preferably 0.0140 inches. Other shape memory materials may be usedas well.

During insertion, a physician can tactilely feel when the eyelet 122 hasbeen slid over the distal lock 110 in order to determine when the distalanchor has been set within a vessel lumen. In addition, if the anchor ismisplaced, it can be collapsed by pulling the eyelet 122 proximally overthe distal lock 110 and repositioning the anchor in the unexpandedconfiguration. The force required to capture the distal anchor ispreferably less than 20 lbs. and more preferably less than 10 lbs.

FIG. 4 also illustrates how the crimp tube 108 is held in place betweenthe distal lock 110 on the proximal side and the stop loop 121 at thedistal end of the support wire 102. The wires of the distal anchor 120exit the distal end of the crimp tube 108 at an angle of approximately45 degrees before looping back over the length of the distal crimp tube108. Therefore, the distal end of the anchor is relatively atraumatic toavoid damage to a vessel during placement.

At the proximal end of the intravascular support is a proximal anchor140 that is preferably formed of a biocompatible, elastic wire such asstainless steel or a shape memory material such as nitinol. As is bestshown in FIGS. 3 and 5, the proximal anchor 140 in one embodiment ismade of a single length of wire having a first end positioned within aproximal crimp tube 112. The wire extends distally from the crimp tube112 and bends radially outward and away from the longitudinal axis ofthe crimp tube 112 before being bent proximally and crossing thelongitudinal axis of the crimp tube 112 in order to form a first leg ofa figure eight configuration. The wire then is bent to form a doubleeyelet or loop 142 around the longitudinal axis of the support wire 102wherein the eyelet 142 has a diameter that allows it to be forced overthe proximal lock 114. After forming the eyelet 142, the wire extendsoutwardly and away from the longitudinal axis of the crimp tube 112before being bent distally over and across the longitudinal axis of thecrimp tube 112 to form the second leg of a figure eight. Finally, thewire is bent proximally and extends into the distal end of the crimptube 112.

Like the distal anchor, the proximal anchor is expanded and locked bysliding the double eyelet 142 of the proximal anchor from a positionthat is proximal to the proximal lock 114 on the support wire to aposition that is distal to the proximal lock 114. As can be seen in FIG.7, the proximal lock 114 has an “arrowhead” shape whereby the proximalend of the lock is bent away from the longitudinal axis of the supportwire at an angle that is less steep than the distal end of the proximallock. The less steep section makes it easier to advance the eyelet 142over the lock in the distal direction than to retrieve the eyelet 142over the proximal lock 114 in the proximal direction. Distal movement ofeyelet 142 cams the less steep proximal surfaces inward to permit eyelet142 to pass distally of the lock 114, then return to their originalspacing to keep eyelet 142 in the locked position.

As can be seen by comparing the proximal anchor 140 with the distalanchor 120 in FIG. 3, the proximal anchor has a larger radius ofcurvature because it is designed to fit within a larger diameter portionof the coronary sinus. The dimensions of the proximal anchor areselected so that the diameter of the proximal anchor in a planeperpendicular to the axis of the lumen in which the anchor is deployedis preferably between 100% and 300%, most preferably between 130% and200%, of the diameter of the lumen prior to deployment. As with thedistal anchor, oversizing the proximal anchor combined with the inherentdeformability and recoverability properties of the anchor material(particularly nitinol or some other shape memory material) enables theanchor to continue to expand from its initial deployment size as thelumen distends and expands over time.

Upon expansion, the proximal anchor circumferentially engages the vesselwall with a radially outwardly directed force that is distributedunequally around the circumference of the anchor by distending thevessel wall in variable amounts along the axial length of the anchor. Aswith the distal anchor, the unequal distribution of force helps theproximal anchor contact the lumen wall securely by creating bumps andridges that are not parallel to the central axis of the lumen. In itsexpanded configuration the proximal anchor's diameter is at least50%-500% and most preferably 100%-300% of the anchor's diameter in theunexpanded configuration. The open cross-sectional area of the lumenthrough the anchor is at least 50% and most preferably 80%-100% of thelumen cross sectional area prior to redeployment of the anchor.

In one embodiment of the invention, the proximal and distal anchors areoriented such that the planes of the anchors are offset with respect toeach other by an angle of approximately 30 degrees. The offset helps theintravascular support 100 seat itself in the coronary sinus and vesselsurrounding the mitral valve in certain mammals. However, it will beappreciated that if the support is designed for other uses, the proximaland distal anchors may be offset by more or less depending upon theanatomy of the intended destination.

FIGS. 6A-6C illustrate cross-sectional views of the crimp tubes in whichthe wires that form the support wire 102 and proximal and distal anchors120, 140 are threaded. In one embodiment, the crimp tubes comprise abiocompatible material such as titanium having a number of holesextending longitudinally through the tube through which the wires arethreaded. In FIG. 6A, a tube 150 has four holes 152, 154, 156, 158positioned in approximately a square configuration within thecircumference of the tube 150. As shown in FIG. 6B, a tube 160 includesfour holes 162, 164, 166, 168 therein that are positioned in a diamondconfiguration. FIG. 6C shows another tube 170 having four holes 172,174, 176, 178. Here the holes 172, 174 lie in a first plane and thesecond pair of holes 176, 178 lie in a second plane that is offset fromthe plane of the holes 172, 174. By changing the orientation of theholes 176, 178 with respect to the holes 172, 174, the relative plane ofwires passing through the holes can be adjusted. Thus in the exampleshown in FIG. 3, the proximal anchor may be formed with a crimp tubesuch as that shown in FIG. 6A or FIG. 6B while the proximal anchor maybe formed in a crimp tube such as that shown in FIG. 6C in order toadjust the angular orientation between the proximal anchor and thedistal anchor. In an alternative embodiment, the crimp tubes at theproximal and distal ends of the support wire 102 are the same and theangular offset between the proximal and distal anchor is achieved bybending the wires at the desired angle. Although the crimp tubes shownuse one hole for each wire passing through the crimp tube, it will beappreciated that other configurations may be provided such as slots orother passages for the wires to pass through.

In another embodiment, the distal and proximal anchors are attached tothe support wire by a wire, such as nitinol wire or other shape memorymaterial. The attaching wire may be spiral wrapped around the base ofeach anchor and around the support wire. In another embodiment, eachanchor may be attached to the support wire by wrapping the anchor wirearound the support wire. In yet another embodiment, the two anchors andthe support wire may be made from a single wire, such as nitinol wire orother shape memory material.

FIG. 8 illustrates one method for delivering an intravascular support I00 in accordance with the present invention to a desired location in thebody. As indicated above, intravascular support 100 is preferably loadedinto and routed to a desired location within a catheter 200 with theproximal and distal anchors in a collapsed or deformed condition. Thatis, the eyelet 122 of the distal anchor 120 is positioned proximally ofthe distal lock 110 and the eyelet 142 of the proximal anchor 140 ispositioned proximal to the proximal lock 114. The physician ejects thedistal end of the intravascular support from the catheter 200 into thelumen by advancing the intravascular support or retracting the catheteror a combination thereof. A pusher (not shown) provides distal movementof the intravascular support with respect to catheter 200, and a tether201 provides proximal movement of the intravascular support with respectto catheter 200. Because of the inherent recoverability of the materialfrom which it is formed, the distal anchor begins to expand as soon asit is outside the catheter. Once the intravascular support is properlypositioned, the eyelet 122 of the distal anchor is pushed distally overthe distal lock 110 so that the distal anchor 120 further expands andlocks in place to securely engage the lumen wall and remains in theexpanded condition. Next, the proximal end of the support wire 102 istensioned by applying a proximally-directed force on the support wireand distal anchor to apply sufficient pressure on the tissue adjacentthe support wire to modify the shape of that tissue. In the case of themitral valve, fluoroscopy, ultrasound or other imaging technology may beused to see when the support wire supplies sufficient pressure on themitral valve to aid in its complete closure with each ventricularcontraction without otherwise adversely affecting the patient. Apreferred method of assessing efficacy and safety during a mitral valveprocedure is disclosed in copending U.S. patent application Ser. No.10/366,585, filed Feb. 12, 2003, and titled “Method of Implanting aMitral Valve Therapy Device,” the disclosure of which is incorporatedherein by reference. Once the proper pressure of the support wire hasbeen determined, the proximal anchor is deployed from the catheter andallowed to begin its expansion. The eyelet 142 of the proximal anchor140 is advanced distally over the proximal lock 114 to expand and lockthe proximal anchor, thereby securely engaging the lumen wall andmaintaining the pressure of the support wire against the lumen wall.Finally, the mechanism for securing the proximal end of theintravascular support can be released. In one embodiment, the securementis made with a braided loop 202 at the end of tether 201 and a hitch pin204. The hitch pin 204 is withdrawn thereby releasing the loop 202 so itcan be pulled through the proximal lock 114 at the proximal end of theintravascular support 100.

In many contexts, it is important for the device to occupy as little ofthe lumen as possible. For example, when using the device and method ofthis invention to treat mitral valve regurgitation, the device should beas open as possible to blood flow in the coronary sinus (and to theintroduction of other medical devices, such as pacing leads) while stillproviding the support necessary to reshape the mitral valve annulusthrough the coronary sinus wall. The combination of the device's opendesign and the use of nitinol or some other shape memory materialenables the invention to meet these goals. When deployed in the coronarysinus or other lumen, the device preferably occupies between about 1.5%and about 5.5% of the overall volume of the section of lumen in which itis deployed.

In many embodiments of the invention, the use of a shape memory materialsuch as nitinol is particularly important. The percentage of shapememory material by volume in the device is preferably between about 30%and 100%, most preferably between about 40% and 60%.

In some instances it may be necessary to move or remove an intravascularsupport after deployment by recapturing the device into a catheter.Prior to deployment of the proximal anchor, the distal anchor may berecaptured into the delivery catheter by simultaneously holding thedevice in place with tether 201 while advancing catheter distally overdistal anchor 120 so that the entire device is once again insidecatheter 200. The distally directed force of the catheter collapsesdistal anchor 120 into a size small enough to fit into catheter 200again. Likewise, after deployment of both anchors but prior to releasingthe securement mechanism as described above, the intravascular supportmay be recaptured into the delivery catheter by simultaneously holdingthe device in place with tether 201 while advancing catheter distallyfirst over proximal anchor 140, over support wire 102, and finally overdistal anchor 120. The distally directed forced of catheter 200collapses anchors 120 and 140 into a size small enough to fit intocatheter 200 again. If the securement mechanism has been detached fromthe device prior to recapture, the device still may be recaptured intothe delivery catheter or another catheter by grasping the proximal endof the device with a grasper or tether and by advancing the catheterdistally over the device.

In one embodiment of the invention, proximal anchor 140 includes arecapture guidance and compression element. In the embodiment shown inFIG. 5, the slope of the two proximal arms 143 and 144 of proximalanchor 140 is small in proximal portions 145 and 146 of the arms, thenincreases in more distal portions 147 and 148 of the arms. This shapeguides the catheter to move distally over the anchor more easily and tohelp compress the anchor to a collapsed shape as the catheter advancesduring recapture.

Likewise, the two proximal arms 123 and 124 of distal anchor 120 have ashallower slope in their proximal portions 145 and 146 and an increasedslope in more distal portions 147 and 148. While recapture of the distalanchor is somewhat easier due to its smaller size compared to theproximal anchor, this recapture guidance and compression featureenhances the ease with which recapture is performed.

FIG. 9 illustrates an alternative embodiment of the intravascularsupport of the present invention. In this embodiment, an intravascularsupport 250 has a support wire 252 and a distal anchor 254 and aproximal anchor 256. In the embodiment shown in FIG. 9, the distalanchor 254 is made from the same wire used to form the support wire 252.As best shown in FIG. 10, the wire used to form the support wire 252extends distally through a distal crimp tube 260 before looping radiallyoutward and returning proximally and across the longitudinal axis of thecrimp tube 260 to form one leg of a figure eight. The wire then windsaround the axis of the suspension wire 252 to form an eyelet 262. Thewire then continues radially outward and distally across thelongitudinal axis of the crimp tube 260 to form the second leg of afigure eight. After forming the figure eight, the wire enters the distalend of the crimp tube 260 in the proximal direction to form the otherhalf of the support wire 252. A distal lock 264 is formed proximal tothe distal crimp tube 260 by outwardly extending bends in the wires thatform the support wire 252. The distal lock 264 prevents the doubleeyelet 262 from sliding proximally and collapsing the distal anchor 254when positioned in a vessel.

As shown in FIG. 11, a distal anchor 256 is constructed in a fashionsimilar to the proximal anchor 140 shown in FIG. 3. That is, theproximal anchor 256 is formed of a separate wire than the wire used toform the support wire 252 and distal anchor 254. The wire of theproximal anchor has one end within a proximal crimp tube 270. The wireextends distally out of the end of the crimp tube and bends radiallyoutward before returning back and across the longitudinal axis of thecrimp tube 270. At the proximal end of the crimp tube 270, the wire ofthe proximal anchor forms a double eyelet 272 around the longitudinalaxis of the support wire 252. The wire then continues radially outwardand distally over the longitudinal axis of the crimp tube 270 to formthe second leg of the figure eight whereupon it is bent proximally intothe distal end of the crimp tube 270.

FIG. 12 shows yet another embodiment of an intravascular support inaccordance with the present invention. Here, an intravascular support300 comprises a support wire 302, a distal anchor 304 and a proximalanchor 306. As in the embodiment shown in FIG. 9, the distal anchor 304and the support wire 302 are formed of the same wire. To form the distalanchor, the wire extends distally through a distal crimp tube 310 andexits out the distal end before extending radially outward and bendingback and across the longitudinal axis of the crimp tube 310 to form oneleg of a figure eight. The loop then forms an eyelet 312 around thelongitudinal axis of the support wire 302 before bending radiallyoutward and distally across the longitudinal axis of the crimp tube 310to form a second leg of the figure eight. The wire then enters thedistal end of the crimp tube 310 in the proximal direction. The supportwire 302 may have one or two outwardly extending sections that form adistal stop 314 to maintain the position of the eyelet 312 once thedistal anchor is set in the expanded configuration.

The proximal anchor 306 is formed from a separate wire as shown in FIG.14. The wire has one end positioned within the proximal crimp tube 320that extends distally outward and radially away from the longitudinalaxis of the crimp tube 320 before being bent proximally and across thelongitudinal axis of the crimp tube 320 to form one leg of the figureeight. The wire then winds around the longitudinal axis of the supportwire to form an eyelet 322 before being bent distally and across thelongitudinal axis of the crimp tube 320 to enter the distal end of thecrimp tube 320 in the proximal direction. As will be appreciated, theproximal crimp tube 320 of the embodiment shown in FIG. 12 holds fourwires wherein the distal crimp tube 310 need only hold two wires.

FIGS. 15-18 show other embodiments of the invention. In the embodimentshown in FIG. 15, the intravascular support has an anchor 400 formed asa loop 404 emerging from a window 406 in a crimp tube 408. Extendingfrom one end 411 of crimp tube 408 is a support strut 410 which connectswith loop 404. Also extending from the crimp tube 408 is a support wire412. Loop 404 and support 410 may be formed from nitinol, stainlesssteel, or any other appropriate material. The intravascular supportincludes another anchor. The intravascular support of this embodimentmay be delivered and deployed in the manner discussed above with respectto the embodiment described above.

FIG. 16 shows another embodiment of an anchor 450 for an intravascularsupport. Anchor 450 is formed from two loops 452 and 454 emerging from awindow 456 and an end 457 of a crimp tube 458. A support wire 462 alsoextends from the crimp tube. Loops 452 and 454 may be formed fromnitinol, stainless steel, or any other appropriate material. Theintravascular support includes another anchor. The intravascular supportof this embodiment may be delivered and deployed in the manner discussedabove with respect to the embodiment described above.

FIG. 17 shows yet another embodiment of an anchor 500 for anintravascular support according to this invention. Anchor 500 is formedfrom two loops 502 and 504 emerging from a window 506 and an end 507 ofa crimp tube 508. A cross strut 505 connects the loops. A support wire512 also extends from the crimp tube. Loops 502 and 504 and strut 505may be formed from nitinol, stainless steel, or any other appropriatematerial. The intravascular support includes another anchor. Theintravascular support of this embodiment may be delivered and deployedin the manner discussed above with respect to the embodiment describedabove.

FIG. 18 is a modification of the embodiment shown in FIGS. 3-7. In thisembodiment, torsional springs 558 of proximal anchor 550 have beenformed as single loops or eyelets in the anchor's wire 552. Thesesprings make the anchor 550 more compliant by absorbing some of theforce applied to the anchor during locking. While FIG. 18 shows aproximal anchor with two springs 558, any number of springs could beused on either the proximal or the distal anchor.

While the preferred embodiment of the invention has been illustrated anddescribed, it will be appreciated that various changes can be madetherein without departing from the scope of the invention. Therefore,the scope of the invention is to be determined from the following claimsand equivalents thereto.

1. A method of recapturing a device deployed in a lumen to modify theshape of tissue adjacent to the lumen, the method comprising: holdingthe device in place within the lumen; advancing a catheter distallywithin the lumen; engaging a distal surface of the catheter with arecapture mechanism of the device; and recapturing at least a portion ofthe device into the catheter.
 2. The method of claim 1 wherein thedevice comprises an anchor, the recapture mechanism being on the anchor,the recapturing step comprising moving the catheter distally to placethe anchor inside the catheter.
 3. The method of claim 2 wherein therecapturing step comprises compressing the anchor.
 4. The method ofclaim 2 wherein the recapture mechanism comprises a surface on theanchor, the engaging step comprising engaging the distal surface of thecatheter with the recapture surface on the anchor.
 5. The method ofclaim 4 wherein the recapture surface on the anchor comprises a firstsurface on the anchor and a second surface on the anchor, the slope ofthe first surface with respect to a wall of the lumen being less thanthe slope of the second surface with respect to the wall of the lumen,the first surface being closer to the wall of the lumen than the secondsurface is to the wall of the lumen, the engaging step comprisingengaging the distal surface of the catheter with the first surface ofthe anchor before engaging the distal surface of the catheter with thesecond surface of the anchor.
 6. The method of claim 2 wherein theanchor comprises first and second proximal arms, and wherein therecapture surface on the anchor comprises a first surface on the firstproximal arm and a second surface on the first proximal arm, the slopeof the first surface with respect to a wall of the lumen being less thanthe slope of the second surface with respect to the wall of the lumen,the first surface being closer to the wall of the lumen than the secondsurface is to the wall of the lumen, the engaging step comprisingengaging the distal surface of the catheter with the first surface ofthe recapture surface before engaging the distal surface of the catheterwith the second surface of the recapture surface.
 7. The method of claim6 wherein the recapture surface further comprises a third surface on thesecond proximal arm and a fourth surface on the second proximal arm, theslope of the third surface with respect to the wall of the lumen beingless than the slope of the fourth surface with respect to the wall ofthe lumen, the third surface being closer to the wall of the lumen thanthe fourth surface is to the wall of the lumen, the engaging stepfurther comprising engaging the distal surface of the catheter with thethird surface of the recapture surface before engaging the distalsurface of the catheter with the fourth surface of the recapturesurface.
 8. The method of claim 1 wherein the recapture mechanism is arecapture surface on the device, the engaging step comprising engagingthe distal surface of the catheter with the recapture surface on thedevice.
 9. The method of claim 1 wherein the device comprises first andsecond anchors, the recapture mechanism being on at least the firstanchor, the recapturing step comprising moving the catheter distally toplace the first and second anchors inside the catheter.
 10. The methodof claim 1 wherein the holding step comprises holding the device inplace with a tether extending proximally from the device.